Presentation prepared for Arsenic in Drinking Water: An International Conference at Columbia University, New York, Nove

1. Presentation prepared for �Arsenic in Drinking Water: An International Conference at Columbia University, New York, November 26-27, 2001�U.S. Federal Regulation of Arsenic in Drinking Water Bruce A. Macler, Ph.D. USEPA Region 9 (415) 972-3569 macler.bruce@epa.gov

2. Arsenic Rule Rule promulgated January 22, 2001 FR 66, #14, pp 6975-7066 Effective date February 22, 2002 MCL proposed at 5 ug/L, set at 10 ug/L Based on cost-benefit balance Used bladder and lung cancer risks 5-year implementation period MCL compliance January 23, 2006 CCR reporting beginning February 22, 2002

3. A Bit of Arsenic Regulatory History Original Public Health Service standard was 50 ug/L Based on non-cancer endpoints PHS standard grandfathered as EPA Maximum Contaminant Level in 1974 1986 Safe Drinking Water Act amendments directed EPA to review, revise arsenic MCL Concern for skin cancer

4. The Safe Drinking Water Act Directs EPA's Regulations Maximum Contaminant Level Goals Not enforceable, but direct MCL "Each MCLG...shall be set at the level at which no known or anticipated adverse effects on the health of persons occur and which allow an adequate margin of safety" National Primary Drinking Water Regulations Enforceable Set as close as feasible to MCLGs Feasible analytical methods and treatment technologies Administrator can adjust MCL for cost reasons Other regulatory applications generally not considered

5. EPA Public Health Goals for DW Standards For contaminants with no threshold for adverse effects (i.e., initiator carcinogens) MCLG = zero as default or positive data for initiation MCL generally set between 1/10,000 and 1/million increased lifetime risk for cancer, based on risk assessments For contaminants showing a threshold for adverse effects (promoter carcinogens, non-carcinogens) MCLG based on Reference Dose (RfD), set to be below any known adverse health effects MCL set as close as feasible to MCLG

6. Arsenic is a Poison Arsenic health effects have been extensively studied A variety of human cancers are associated with arsenic ingestion Lung, bladder, prostate, skin, liver� Arsenic inhibits chromosomal repair, enhances cancer progression Circulatory and neurological damage, diabetes also can occur Arsenic inhibits mitochondrial respiration High disease levels seen in populations drinking water with arsenic 5-20 times higher than current 50 ug/L MCL

7. New Arsenic Health Worries We don�t lack health data� 100�s of arsenic publications in last two years Arsenic appears to act as endocrine disrupter to block glucocorticoid action May affect diabetes, hypertension, cancer Acts as low as 10 ug/L Dimethylarsinic acid is toxic Causes DNA strand breaks in lung tissue (complete carcinogen) Promotes bladder, kidney, liver and thyroid cancers Methylation NOT a detoxification mechanism

8. Arsenic Regulatory Issues Money Affected drinking water purveyors Other affected parties Health effects/ regulatory benefits Treatment

9. Affected Drinking Water Systems, I ~59,000 community water systems in US ~10,000 use surface water, ~49,000 use ground water About 2500 utilities serve >10,000 people >90% of smallest systems use groundwater Highest arsenic levels are in small groundwater systems 3300 GW systems, 90 SW systems >10 ug/L 3300 small (<10,000), 90 large

10. Affected Drinking Water Systems, II Most affected systems are very small, rural Smaller systems not really utilities Few have a full-time operator Little or no treatment infrastructure Limited financial resources Most affected systems have had few regulations to follow up to now Basically, implementation starts from scratch

11. Other Affected Parties Drinking water MCLs used for Superfund and other hazardous waste cleanups While not directly applicable, these are considered �relevant and appropriate regulations� Groundwater cleanups may be set at MCL Mine wastes, oil extraction brines, coal flyash often high in arsenic Arsenic may be dominant risk in site assessments Cleanup costs are less important Costs could be greater than for all drinking water

12. Health Effects Issues, ISafe Drinking Water Is arsenic a public health problem in the US? SDWA goals versus risk perceptions Safety is in the eye of the beholder SDWA has de minimus public health risk goal MCLs have been set with estimated risks between 1/10,000 - 1/million excess lifetime Not law, but precedent There are no �bodies in the streets� in U.S. from arsenic

13. Health Effects Issues, IIRisk Assessment Epidemiology, medicine can at best resolve risks >1/100 level For arsenic, exposures not high enough for epidemiology to find disease in U.S. Risk assessments can extrapolate data to lower exposures and risk levels Regulatory risk assessments are conservative, generally go to upper risk boundaries Arsenic has always been here, so some biochemical detoxification mechanism must exist Real risks could be lower

14. Treatment Issues For smaller GW systems, going from nothing to something For larger GW systems, wellhead treatment at multiple wells Waste disposal hassles and costs Peripherals: land, permits, human resources, NIMBYs, etc

15. More Arsenic Regulatory History In early 1990�s, new cancer concerns were growing But strong opposition by oil, extractive and drinking water industries 1996 SDWA amendments featured arsenic, cost-benefit decision-making EPA proposed 5 ug/L as arsenic MCL in June 2000 EPA promulgated MCL at 10 ug/L in January 2001 New Administration postponed effective date, set up review

16. What Was Reviewed? EPA Administrator Whitman said, �It's only a review. The MCL may stay the same or even go down.� National Academy of Sciences reviewed health data and risk assessments from 3-20 ug/L National Drinking Water Advisory Committee reviewed cost and technologies materials EPA Science Advisory Board reviewed benefits analysis

17. NAS Health and Risk Review The Academy�s National Research Council reviewed EPA�s arsenic risk assessment Reviewed use of Taiwanese studies and Taiwanese populations Evaluated data for 1% (ED01) cancer risk level Considered EPA�s analysis of mode of action and dose-response uncertainties Judged whether EPA risk estimates for 3, 5, 10 and 20 ug/L were consistent with current science

18. NAS Conclusions Data from Taiwan, Chile indicate high risks for cancer Appropriate for risk assessment use Utah study too problematic for use Use linear approach to extrapolate from 1% (ED01) cancer risk to 1/10,000 regulatory risk level Sublinear extrapolation not justified Substantial variation in human response needs to be incorporated Consider using U.S. background cancer levels Epidemiological studies unlikely to show effects in U.S.

19. NAS: Cancer Risks from Arsenic Ingestion NAS estimated arsenic-associated lung and bladder cancers Bladder cancer risk about 12-23/10,000 @ 10 ug/L Lung cancer risk about 14-18/10,000 @ 10 ug/L (EPA had estimated bladder + lung cancer at 0.6-3/10,000 @ 10 ug/L) Other cancers not quantified, but add risk Overall 1% cancer risk level < 50 ug/L

20. EPA SAB Benefits Review Science Advisory Board examined how EPA valued benefits from Arsenic Rule Reviewed quantification of cancer costs, and benefits from not getting cancer Also reviewed quantification of costs of other diseases Recommended EPA quantify ischemic heart disease, diabetes mellitus and skin cancer Suggested EPA consider quantifying prostate cancer, nephritis, nephrosis, hypertension, hypertensive heart disease and non-malignant respiratory disease Said EPA should consider latency adjustment Net result could increase or decrease benefits of Rule

21. NDWAC Treatment Cost Review Examined costing methodologies, assumptions, information and national estimate of system costs for the Arsenic Rule Concluded that EPA�s estimate was credible Offered a variety of improvements New technologies will lower costs Necessary related activities add to costs Net result unlikely to significantly change national costs

23. What�s Next? EPA let MCL stand at 10 ug/L without comment on reviews Implementation by small systems will be a challenge Need simple, user-friendly treatment Must be easy to design, �off-the-shelf� to cut costs Need to find and train operators Need money Need to change some minds